Improvement in machines for extracting broken screws



w. n. moan. MACHINE FOR EXTBAG'I'ING' BROKEN SCREWS.

* Patented Feb.22, 1876.

UNITED STATES PATENT OFFICE.

' WILLIAM H. THORNE,0F PHILADELPHIA,PENNSYLVANIA, Assrenon'ro HIMSELF,I. N. DE HAVEN, AND JOHN G. DA COSTA, OF SAME PLAOE.

IMPROVEMENT IN lVIACHlNES FOR EX fI'R ACTlNG BROKEN SCREWS.

Specification forming part of Letters Patent No. 174,030, dated February22, 1876; application filed December 17, 1875.

To all whom it may concern Be itknown that 1, WILLIAM H. THORNE,ofPhiladelphia, Pennsylvania, have invented a Machine for ExtractingBroken Screws,

- of which the following is a specification:

The object of my invention isto readily withdraw from axle-boxes andother objects the stems of set-screws from which the'heads I have beenaccidentally broken, and this objectI attain in the-manner which I willnow proceed to describe, reference being bad to the accompanyingdrawing, in which- Figure 1 is a view illustrating the mode ofextracting the threaded stem of a broken'setscrew; Fig. 2 'a perspectiveview ot'the mahaving as many sides as are necessary for presentingcomparatively sharp edges, which, under the pressure applied to the bit,indent the sides of theorifice a. By manipulating a suitable handle orwrench applied to the bit,

the latter becomes the medium through which the stem maybe unscrewedfrom the metal B.

' The heads of screws which confine the covers of the axle-boxes totheinplaces are frequently broken, and the machine which forms thesubject of myinvention has been especially designed for the purpose ofextracting such broken screws. D is a frame or stand, the base of whichis constructed, as shown in Fig. 4 so as to carry four horizontalset-screws, b, for the ready and secure attachment of the said stand to,and its removal from, the end of the axle-box, as seen in Fig. 2; To thetop of this stand is secured a carrier, G, by means of a set-screw, e,which passes through a slot in the said carrier, so that theilatter'ca-n be turned in any direction desired, or moved to I and fromthe axis on which it is turned, and securedafter adjustment. n

The outer end f of the carrier is threaded for the reception of atubular screw, H, which is provided at-the top with a handle, h. In

the interior of this screw is a drill-spindle, F,

position that a drill attached to the spindle F shall be presented tothe stem of a broken screw, the carrier is secured, the dlrill-spindleturned by the handle i, and fed by manipulating the handle of thetubular screw.

When an orifice of sufiicient depth has been bored in the stem, thescrew H is elevated,

broken set-screw, until-the edges of the bit indent the sides of thesaid orifice, when, by turning the handle 2' in the properdirectio n,and at the same time turning the tubular screw, the broken stem may bequickly withdrawn. 7

I claim as my invention- The stand I), with its horizontal setscrews 1),and carrier G, admitting of being adjusted on the said stand, with thetubular screw H and spindle F.

In testimony. whereof I have signed my name to-this specification in thepresence of two subscribing witnesses.

WM. 11. THORNE.

